The Research On Xiluodu Valley Deformation Mechanism Based On Hydraulic Coupling Test And DDA Analysis

With the rapid development of China's water conservancy projects,a number of high arch dams such as Jinping I,Xiluodu,Xiaowan,etc.have been completed and entered into operation.However,these arch dams all have valley amplitude deformation with different amplitude after storage,and the deformation time is long,showing strong time-dependent characteristics.The safety problem of the dam caused by the valley amplitude deformation is becoming more and more serious.In order to provide a basis for long-term use,maintenance and stability evaluation of the dam,and to ensure the safe operation of water conservancy facilities,it is necessary to study the mechanism of valley deformation.Based on the characteristics of Xiluodu valley amplitude deformation,this paper carried out research work on the mechanism of valley amplitude deformation using water-rock coupling mechanical test and DDA numerical simulation.Through the hydraulic coupling true triaxial test of the fractured rock mass in the dam area and the direct shear of interlayer dislocation zone based on the experiment,the timedeterioration model of the fractured rock mass under hydraulic coupling is obtained.Based on the DDA method,the effect mechanism of the time-deterioration of the fractured rock mass parameters and the initial stress field stress release on the deformation of the Xiluodu valley is studied.The main research contents of this article are as follows:(1)Introduce the engineering geological background of Xiluodu dam area,study and analyze its deformation characteristics based on Xiluodu valley amplitude deformation monitoring data,and make an engineering analogy with other high arch dam valley amplitude deformations to obtain its deformation characteristics and commonality.(2)Based on the hydraulic coupling true triaxial test of Xiluodu fractured rock mass and the direct shear test of interlayer dislocation zone,the variation law of the deformation and strength characteristics of basalt fractured rock mass and interlayer dislocation zone affected by water storage was studied and obtained Aging model for strength parameters of fractured rock mass.(3)Based on the discontinuous deformation analysis method,the effect of water storage on the change of the initial stress field is studied,and the numerical simulation analysis of the Xiluodu valley amplitude deformation is carried out based on the timedependent deterioration model of the strength parameter of the fractured rock mass obtained by the field coupling hydraulic coupling.